1. Field of the Invention
The present invention relates to an electromagnetic relay, a joining structure for a hinge spring and a yoke in the electromagnetic relay, and a flux penetration preventing structure, and more particularly, to a joining structure for joining a hinge spring to a yoke in the electromagnetic relay, and a terminal side sealing structure for an anti-flux type electromagnetic relay mounted on a printed circuit board.
2. Description of the Related Art
In the construction of an electromagnetic relay, for example, a coil is wound around an iron core to construct an electromagnet, and a yoke as a component to complete a magnetic circuit with it is fastened rigidly to the iron core and an armature is rotatably mounted in such a manner as to bridge between the yoke and the head of the iron core of the electromagnet to construct an electromagnet structure. Then, one end of this electromagnet structure is fixed to the yoke and the other end thereof is made to engage with the armature, the rotatable movement of the armature being supported by a plate-like hinge spring formed from a resilient member.
Incidentally, assembling the hinge spring to the yoke in the electromagnetic relay requires assembling equipment (such as a crimping tool or a welder). This has presented the problem in that the assembling requires many assembling steps and takes a lot of time.
Further, in the prior art, when mounting the electromagnetic relay on a printed circuit board, the printed circuit board is passed through a high-temperature solder bath, for example, and the electromagnetic relay with solder applied to the terminal leads thereof is mounted rigidly on the printed circuit board. At this time, there is a possibility that flux may rise from the solder bath and penetrate into the interior of the electromagnetic relay; to prevent this, the bottom of the electromagnetic relay (base block) is sealed.
In constructing an electromagnetic relay having such a flux penetration preventing structure, a liquid sealant is filled into the base of the base block and the liquid sealant is then heated to form the sealing structure. This, however, has entailed the problem that, when the liquid sealant cures after heating, bubbles are trapped in the sealing structure, forming pinholes and defeating the purpose of the sealing.
The prior art electromagnetic relay and problems associated with the prior art will be described in detail later with reference to drawings.